JP3347722B2 - Integrated circuit testing method and apparatus - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method and apparatus for testing integrated circuits and, more particularly, to a method for mounting a large number of elongated flexible strips, such as motion picture film. The present invention relates to a method and apparatus used for automatically testing integrated circuits.

[Conventional technology and its problems]

One method of manufacturing and testing integrated circuits is a process known as tape automated bonding. This process utilizes an elongated flexible strip, such as a standard motion picture film, having a thin layer of conductive material, such as copper, deposited on the surface. This layer is photo-etched to form a plurality of continuous lead frames that are substantially identical to one another. Next, the chip or die of the integrated circuit is bonded to the leads of each frame.

The strip typically has sprocket holes along its two sides that mesh with the rotating sprocket wheel, and throughout the various stages of the manufacturing and testing process, the lead frame and associated die mounted thereon. Pull the strip with. Like the motion picture film, the strip with the lead frame and the die mounted thereon is wound up and unwound from the reel during the manufacturing and testing process. At the end of the process, the strip is cut into pieces, each comprising a lead frame and an associated die, which are packaged to form the final product.

The die is tested while on the strip to determine that it meets operating specifications and to verify that the electrical connection between the lead and the die is correct. Such a test is performed by a probe test card having a plurality of probes extending downward. Each probe has a relatively thin line to which a downward bias is applied.

In one test configuration, the strip with the die mounted upwards is pulled by a sprocket just below the probe test card. The test equipment periodically stops the movement of the strip so that each die is temporarily below the probe test card. When in such a position, the card is lowered until each probe is pressed against a test pad formed on a copper lead of the frame directly below the card. Thereafter, a voltage is applied through the probe and measured to confirm that the die meets operating specifications and that the leads are properly connected to the die. Then the probe test card rises,
The strip advances until the next die in the sequence stops just below the probe test card. The card goes down again to test the next adjacent die and lead connections as described above. The above process is repeated until each die on the strip has been tested.

The above-described conventional methods and apparatus have several disadvantages. As noted above, the probes on the card are very thin and, depending on the integrated circuit being tested, may have more than 100 and relatively small spacing between the probes.

If the probe bends and its tip displaces a distance equal to the thickness of a human hair, the probe will not be able to abut the test pad on the lead frame that it is designed to make electrical contact with . In such a situation, the test is likely to determine that the die or lead connection or both are defective. Since the tester is provided with a punch that cuts the defective circuit from the strip, many good dies that are properly connected to the corresponding leads may be punched from the strip.

Probes typically bend in one of two ways. First, as the strip starts and stops under the control of test equipment, poor feed may cause the strip to deflect slightly, lifting up the section of the strip on which the test pad rests. When the probe test card is lowered in this state, the probe above the bent strip is forced into the strip, causing the strip to deflect. Also, the probe can bend even if the strip moves a small amount while the probe is in contact with the test pad.

The automatic test process typically stops every one to two hours to correct any damage to the probe by the card.

[Object of the invention]

It is a general object of the present invention to provide a method and apparatus for testing an integrated circuit that eliminates the above-mentioned disadvantages of the prior art.

It is a more specific object of the present invention to provide a method and apparatus for increasing the yield of integrated circuits by reducing the number of circuits that are incorrectly indicated as bad.

Another specific object of the present invention is to provide a method and apparatus that reduces maintenance on test equipment.

Yet another object of the present invention is to provide a method and apparatus for extending the life of a test instrument.

It is yet another object of the present invention to provide a method and apparatus for increasing the speed of integrated circuit production and testing by reducing the downtime required for test equipment maintenance.

It is another general object of the present invention to provide a method of making an integrated circuit tester that achieves the objects set forth above.

The present invention comprises a method and apparatus for testing an integrated circuit of the type having a die mounted on a flexible strip and in electrical communication with a plurality of test pads formed on the strip. . Selected segments of the strip on which the integrated circuit die is mounted are positioned relative to the substantially flat strip support. A portion of the strip is pressed against the strip support and the test probe is pressed against the selected test pad. The integrated circuit is tested, after which the probe is lifted from the pad.

The apparatus of the present invention includes a strip support member that is substantially flat and can position a selected strip segment on which an integrated circuit is formed.
A probe test card with a plurality of probes extending therefrom has a first location away from the strip support member and a second location where the probes are in electrical contact with the test pad when the strip portion is in such a location. You can move between the positions. A compression member having a substantially flat surface is mounted on the probe card adjacent the probe and is configured and arranged to press a portion of the strip against the strip member when the probe card is in the second position. .

The present invention also includes a method of making a tester that includes the step of creating at least one test pad opening that exposes a selected test pad on a flexible strip when the plate is pressed against the strip. . A die opening is drilled in the plate to receive the die therein when the plate is pressed against the flexible strip. The plate is mounted on a probe test card and movement of the plate is such that the plate extends beyond the test probe and a second position where the probe in the probe test card extends through the test pad opening. Made between. The plate is biased toward the first position.

The above and other objects, features, and advantages of the present invention will become more readily apparent from the following detailed description of embodiments, which proceeds with reference to the accompanying drawings.

(Example of the invention)

Referring to FIG. 1, indicated generally at 10 is a probe test head constructed in accordance with the present invention. The probe test head 10 is mounted on a conventional integrated circuit test apparatus (not shown) described below. Included are a probe test card 12, a probe guard plate 14, and a strip support member 16. Probe guard plate 14 is referred to herein as a compression member and a substantially planar plate.

Flexible strip 18 is similar to movie film,
Three integrated circuit chips or dies 20, 22, 24 are mounted. The die 22 and a portion of the strip 18 are best seen in FIG. Each die is substantially identical to one another and has the same circuitry formed thereon. Strip18
Is wound on a supply reel (not visible) mounted at one end to a test device to the left of die 20 in FIG. 1 and at another end to a take-up rail mounted to the test device to the right of die 24. (Not visible). The strip 18 has holes 26, 28 formed adjacent to both sides thereof, similar to a plurality of equally spaced sprocket holes. These holes are on the rotatable sprocket wheel (not visible) of the test equipment on which the probe test head 10 is mounted.
Can be engaged.

As the sprocket wheel rotates, the strip 18 is pulled across the strip support 16 and the strip is rewound from the supply reel. As the strip moves, the take-up wheel rotates and the strip is wound on the take-up wheel. Since the test equipment periodically stops the sprocket and take-up reel, each die temporarily occupies the position of die 22 in FIG.

Referring again to FIG. 2, generally designated at 30 is the lead frame connecting the dies 22. FIG. The lead frame 30 is formed on the strip 18 by depositing a thin metal layer on the strip 18 and then photo-etching this layer to form the lead pattern shown in FIG. The lead frames 32, 34 are shown only partially, but are substantially the same as the lead frame 30, and respectively correspond to these in the same manner as the die 22 is connected to the lead frame 30. Dies 20, 24 are connected. Each lead frame 30, 32, 34 and the die associated with each frame is on a separate segment 36, 38, 40 of the strip 18. The dashed line in FIG. 2 shows the boundaries between the segments 36, 38, 40 of the strip.

The lead frame 30 has two annular pads 44 and 48. These toroidal pads 44, 48 are not electrically connected to the die 22, and will be used to align the strip 18 with the probe test head in a manner more fully described hereinafter. 4 test pads similar to test pad 50
Arranged in rows 52, 54, 56, 58 of books, forming a square on segment 36. Each test pad in columns 52, 54, 56, 58 is electrically connected to a selected portion of the circuitry of die 22. The dies in each other segment of strip 18 are similarly connected to the associated lead frame.

Now consider the structure of the probe test card 12 shown in FIGS. 1, 3, 4, and 5. FIG. The probe test card is mounted on a transparent plastic plate 60. The plastic plate 60 is substantially square and has a pair of opposing sides (62, 64 in FIG. 1). Another pair of opposing sides (not visible) define the other two sides of the plastic plate 60. The plastic plate 60 has a lower square portion 61 having a pair of opposed substantially parallel sides 63, 65 visible in FIG. The sides 63, 65 are indicated by dashed lines in FIG. 4 and indicate the position of the lowered portion 61 relative to the probe guard 14, as will be described more fully hereinafter. Opposite sides 67 and 69 of the square portion 61
The boundary of the square portion 61 placed at a lower position along with the sides 63 and 65 is also defined as shown by a virtual line in the figure.

The plastic plate 60 is fixed to a plate support member 70 having a square opening 72. The plate support 70 can be moved vertically under the control of the test equipment in the manner described hereinafter. A pair of screw holes 66 and 68 are plastic plate as shown
It is formed through the plate 60 and the plate supporting member 70.

The probes in the four rows 74, 76, 78, 80 (FIG. 4), one of which is the probe 82 in row 74, extend downward from the underside of the plastic plate 60. Each probe in rows 74-78 is provided with a thin line extending through a vertical hole in the lower square section 61 of the plastic plate 60. Each probe is received in a flexible tube, only some of which are shown generally at 84 in the drawings for purposes of illustration.

One end of each tube 84 is in contact with the upper surface of the plastic plate 60, and the other end is fixed to a plurality of brackets (not shown) attached to the plate support member 70. A spring is installed between each probe wire and its associated bracket to push the probe wires downward as seen in FIG.
Thus, if the probe line is in contact with the structure during the downward movement of the plate support member 70, the probe line will be pushed upward while receiving a downward biasing force on the structure.

At the end of the description of the probe card 12, four holes, two of which are holes 86 and 88, are formed below the square portion 61. Holes 86 and 88 each have a spring 9 in it
Accepts 0 and 92. In FIG. 1, each spring 90, 9
2 is compressed between the ends of the associated holes 86, 88 and the top surface of the probe guard plate 14. Another two holes (not visible) are formed below the lower placed square portion 61 and have springs therein, one of which is a spring 94, but each spring has End of associated hole and guard plate14
As in the case of the springs 88 and 90, a biasing force is applied thereto. In FIG. 4, the lower part of the springs 90, 92, 94 can be seen in the same way as the lower part of the spring 96 located just below the relevant hole (not shown) in the square part 61.

Now consider the structure of the probe guard plate 14 and how it connects to the probe test card 12. In this embodiment of the invention, the guard plate is made of hard anodized aluminum and is therefore light, flat (under its side) and provides strong protection and does not conduct electricity. The protection plate 14 has a flat surface 10 formed on its lower side.
It has a substantially flat plate 98 with zeros.

A pair of opposing substantially parallel end members 102, 104 form a guard plate.
Fourteen opposite ends are formed. Each end member 102, 104
There is a square part placed in the lower position of the plastic plate 60
Upright surfaces 106, 1 substantially parallel to adjacent sides 63, 65 of 61, respectively
There is 08. Each end member 102, 104 is a bolt 110, 112, respectively.
It has. Each of the bolts 110 and 112 is the bolt 11 in FIG.
0 is threadably engaged in the hole such that 0 is threadably engaged in the threaded hole 114. The spacer 116 is received through a hole formed through the plastic plate 60, and the axis of the machine screw 110 is received through the spacer 116. The washer 120 is provided between the head of the machine screw 110 and the upper surface of the plastic plate 60. Machine screw 110, machine screw, washer 1
20, the spacer 116 and the guard plate 114 are fastened in the screw holes 114 so as not to move relative to each other.

Bolt 112 may have substantially identical spacers and washers in end member 104 in the same manner as shown and described in connection with bolt 110.
It is fixed to.

Plate 98 (FIG. 3) has a substantially square opening 12 therethrough.
2 are provided and are referred to herein as die openings. Four elongated probe openings 124, 126, 128, 130 are defined through plate 98 under each of the probe rows 74, 76, 78, 80, respectively. The probe opening 124 can also be seen in FIG.

Four circular holes 132, 134, 136, 138 are made in the corners through the plate 98, the center of the holes forming a square corner.

Turning now to the operation of the preferred embodiment, turning to FIGS. 1-5, the test equipment to which the probe test head 10 is attached, as seen in FIG. Move strip 18 to the right. The strip 18 stops periodically, thus positioning each die, such as the die 22, just below the die opening 122. After that, the plate support member 7
0 is 5th from the position in FIG. 1 under the control of the test equipment.
Move down to the position shown. As the downward movement continues, surface 100 contacts the upper surface of lead frame 30 above segment 36 of strip 18. After the surface 100 has so contacted the lead frame, the subsequent downward movement compresses the springs 90, 92, 94, 96, thereby causing the strip 18 and the lead frame thereon to be protected by the guard plate 14 and the strip support. Subject to pressure between 16 and. All of the foregoing occurs before probe ends, such as the lower end of probe 82, extend through their corresponding probe openings, such as probe opening 124.

After the guard 14 has so pressed the strip 18,
Subsequent downward movement pushes the probes through the probe openings in the guard plate 14 and under each probe row. 4th
Referring to the figure, the probes in row 74 are received in probe openings 124 and the probes in rows 76, 78, 80 are received in probe openings 126, 128, 130, respectively. As the downward movement of the plate 60 continues, the tip of each probe strikes the test pad below it and makes electrical contact with the pad. The downward movement of plate 60 continues until a probe, such as probe 82 in probe opening 124, is pushed slightly upward against plate 60 and against the biasing force applied to the probe. Thus, each probe is pressed against its corresponding test pad, just as probe 82 is pressed against test pad 50.

The biasing force of the springs 90, 92, 94, 96 is large enough to completely crush the buckle that may lift a portion of the strip 18 if the strip 18 experiences a misfeed as it moves. Thus, as the probe approaches the strip 18, the strip 18 becomes completely flat, and the raised surface against which the probe can bend when the plate 60 moves to the position shown in FIG. Does not occur.

Using the probe test head 10 and strip 18 of the configuration shown in FIG. 5, voltage can be applied to the selected probe while the response of the integrated circuit is measured with the other probe to ensure that the die 22 meets operating specifications. It is determined whether the connection between the lead frame 30 and the die is correctly performed.

Upon completion of the test, the branch support 70 moves upward under the control of the test equipment, lifting the probe from the test pad. After the probe has completely separated from the test pad, the spring continues to push the guard 14 against the strip 18 until the guard 14 is in its fully lowered position. That is,
A washer, such as washer 120 associated with bolts 110, 112, again contacts the upper surface of plate 60, causing the probe test head to be in the state shown in FIGS.
Surface 100 will still rest on the lead frame of strip 18. Thereafter, plate 60 continues to move upward through the position of FIG. 3 to the position shown in FIG. It can be seen that the guard plate 14 presses the strip 18 firmly against the strip support member 16 at any time during the time the probe is in contact with the test pad. Such tracking begins before contact of the probe and continues until after the probe has been lifted from the pad. This feature prevents the strip 18 from moving while the probe is in contact with the test pad, and thus may cause the probe to move in response to the movement of the strip while the probe is pressed against the test pad. Bending is prevented.

The foregoing may be accomplished by moving the strip support member 16 and the strips supported thereon toward the probe card while the probe card is stationary, or by moving both the probe card and the strip support member toward each other. It should be noted that this can be done by moving towards.

After the plate support 70 returns to the position of FIG. 1, the strip 18 moves to the right again, stopping the die 20 just below the die opening 122, ie, at the same position as the die 22 of FIG. The member 70 starts to move downward again, and the test process as described above is repeated.

The pads 44, 48 of FIG. 4 allow the strip 18 to be aligned on the strip support 16. This can be done by looking through the transparent plastic plate 60 and the holes 132, 136 and moving the strip until it takes the position shown in FIG.

Although not visible in the figures, plate 60 has a pair of rings formed thereon that are used to precisely align the strips. This ring is pad 44, 48
, But about twice the diameter. If the alignment is correct, the pads 44, 48 will have holes as shown in FIG.
It can be seen through 132, 136 and comes to the center of the ring (not visible) formed on the plate 60.

Turning now to FIG. 6, shown is the probe test card 12 and support member 70 removed from the test equipment for probe repair. A pair of clamps 140, 142 are attached to the plate support member and the probe test card 12 by bolts. One of these halts is a bolt 144. The tip of the probe, such as the tip of the probe 82, thus extends above the plate 98 and is in a position such that an alignment force is applied thereto.

Illustrating the principles of the present invention by its preferred embodiment,
Having described, it should be apparent to those skilled in the art that the configuration and details of the invention may be modified without departing from such principles. Therefore, it is to be noted that all modifications falling within the spirit and scope of the appended claims fall within the scope of the present application.

〔The invention's effect〕

As described above in detail, according to the present invention, it is possible to prevent an error in a test of an integrated circuit and damage to a probe.

[Brief description of the drawings]

1 is a side sectional view of the probe test head, FIG. 2 is a 2-2 partial sectional view of the structure shown in FIG. 1, FIG. 3 is a partially enlarged view of a lower part of the structure shown in FIG. 4 is a partial cross-sectional view of the structure shown in FIG. 1 taken along line 4-4, FIG. 5 is a diagram showing the structure shown in FIG. 3 in another operating state, and FIG. It is a figure showing the state where it was removed. 10: Probe test head 12: Probe test card 14: Probe protection plate 16: Strip support member 18: Strip 20, 22, 24: Die 26, 28: Hole 30, 32, 34: Lead frame 36, 38, 40: Segment 44,48: Ring pad 50: Test pad 60: Plastic plate 61: Square part 62, 63, 64, 65, 67, 69: Side 70: Plate support member 82: Probe 84: Tube 90, 92, 94: Spring 102, 104: End member 116: Spacer 120: Washer 122: Die opening 124, 126, 128, 130: Probe opening 140, 142: Clamp

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-274745 (JP, A) JP-A-2-275376 (JP, A) JP-A-1-318246 (JP, A) JP-A-59-1984 161833 (JP, A) JP-A 1-236638 (JP, A) JP-A 1-163335 (JP, U) JP-A 2-120085 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/66 G01R 31/26

Claims (17)

(57) [Claims] 1. A die having the following steps (a) to (g), sequentially mounted on a flexible strip, and electrically connected to a plurality of test pads formed on the strip. A method for testing an integrated circuit including: (A) positioning the segment of the strip on which the integrated circuit die is mounted relative to the substantially flat strip support; (B) advancing the strip against the strip support until the selected integrated circuit is in a position for testing. (C) pressing a part of the strip against the strip support member using a flat plate provided with an opening. (D) inserting a test probe into an opening in the plate after the strip has stopped moving in response to pressing against the plate. (E) pushing the inserted test probe toward each of the selected test pads. (F) testing the integrated circuit. (G) lifting the test probe from the test pad. 2. The method of claim 1, wherein the flat plate has a die opening large enough to receive a die, and the step of pressing a portion of the strip against the strip support member includes receiving the die in the die opening. The method of claim 1, further comprising the step of moving the plate toward the strip in a state, and forcing the plate against the strip. 3. The method according to claim 1, further comprising the following steps (a) to (e), wherein said step is mounted on a flexible strip and electrically connected to a plurality of test pads formed on said strip. Of manufacturing test equipment for integrated circuits. (A) a test pad opening that exposes selected test pads on the flexible strip and receives test probes without contacting the plate when the plate is pressed into the strip; Providing a dimension to at least one of said plates. (B) creating a die opening in the plate to receive the die as the plate is pressed against the flexible strip. (C) mounting the plate on a probe test card. (D) allowing the plate to move between a first position ahead of the plurality of probes on the probe test card and a second position where the probes extend through the test pad opening; Step to do. (E) applying a force to the plate toward the first position. 4. An integrated circuit comprising the following steps (a) to (i), including a die sequentially mounted on a flexible strip and electrically connected to a plurality of test pads formed on said strip. How to test a circuit. (A) providing a probe test card from which a plurality of probes extend downward. (B) mounting a flat plate having an opening under the probe test card; (C) advancing the selected strip segment on which the integrated circuit die is mounted on a substantially flat strip support member in a lateral manner. (D) lowering the probe test card or raising the strip support member until the flat plate presses a portion of the strip against the strip support member. (E) further lowering the probe test card or raising the strip support member until the probe is inserted into the opening. (F) pushing the inserted probe to the selected test pad. (G) testing the integrated circuit. (H) raising the probe test card or lowering the strip support member until the probe is on the flat plate. (I) further raising the probe test card or lowering the strip support member until the pressing on the strip is stopped. 5. The method according to claim 4, wherein the step of mounting the flat plate includes the following steps (b-1) and (b-2). (B-1) mounting the flat plate under the probe test card substantially parallel to the probe test card. (B-2) a lower position where the tip of the probe extending from the lower side of the probe test card is above the upper surface of the flat plate, and the tip of the probe protrudes from below the lower surface of the flat plate. Allowing the plate to move between an upper position. 6. The step of further lowering the probe test card or raising the strip support member until the probe is inserted into the opening, wherein the step of lowering the probe test card or the raising of the strip support member comprises the step of: 5. The method according to claim 4, comprising the step of lowering. 7. The probe includes a pair of alignment marks, the probe test card includes a corresponding pair of alignment marks, and comprises the following steps (a) and (a): 5. The method of claim 4, wherein positioning is on a test card. (A) viewing the alignment marks on the strip through the corresponding openings. (B) aligning the alignment mark on the strip with the alignment mark on the probe test card. 8. An integrated circuit having a die mounted on a flexible strip and electrically connected to a plurality of test pads formed on the flexible strip, the die having the following (a) to (d). A device for testing circuits. (A) a substantially flat strip support on which a selected strip segment on which the integrated circuit is mounted can be located; (B) between a first card position where a plurality of test probes extend and are separated from the probe support member and a second card position where the tip of the probe is in electrical contact with the test pad; Probe test card that can move relatively with. (C) a first flat plate position mounted adjacent to the probe on the probe test card and prior to the tip of the probe; and the strip when the probe test card is in the second card position. A flat plate movable between a second flat plate position for pressing a part of the flat plate against the strip supporting member. (D) provided on the flat plate, wherein the flat plate is
An opening sized for the tip of the probe to pass when moving from the plate position to the second plate position and for the probe not to contact the plate under all operating conditions of the device. 9. The flat plate, when the strip support member of the probe test card is relatively moving from the first card position to the second card position, and the tip of the probe is in the opening. 9. Apparatus according to claim 8, including means for pressing a portion of the strip against the strip support before entering. 10. The apparatus according to claim 8, further comprising biasing means for applying a force to said flat plate toward said first flat plate position. 11. The flat plate of claim 8, wherein the flat plate has a die opening large enough to receive the die when the flat plate presses a portion of the strip as described above. An apparatus according to claim 1. 12. The apparatus according to claim 8, wherein the following items (a) to (c) are provided. (A) A pair of alignment marks formed on the strip. (B) A pair of corresponding alignment marks formed on the probe test card. (C) The alignment mark provided on the flat plate so that the alignment mark on the strip can be visually checked, and the alignment mark on the strip can be aligned with the alignment mark on the probe test card. A pair of openings. 13. A test probe protector for use with an integrated circuit test apparatus having a test probe card, said test probe card being spaced from a flexible strip having a die and a plurality of test pads provided thereon. The first
And a test probe provided with the following (a) to (f) wherein the tip of the test probe on the test probe card is movable between a second position where the tip of the test probe is in electrical contact with the test pad. Protective body. (A) mounted on the test probe card adjacent to a test probe, wherein the probe test card is
A substantially flat plate that presses the flexible strip as it moves from the second position to the second position. (B) means for allowing the plate to move toward and away from the test probe card. (C) means for limiting the maximum travel of the plate away from the test probe to a first plate position where the plate is ahead of the tip of the test probe. (D) the maximum travel of the plate towards the test probe,
Means for limiting the probe tip on the test probe card to a second plate position where the tip of the probe protrudes from the plate. (E) biasing means for applying a force to the plate toward the first plate position. (F) provided on the plate, as the plate moves from the first plate position to the second plate position, the tip of the probe passes through, and in all operating conditions of the test probe protective body, An opening sized so that the probe does not contact the plate. 14. The biasing means includes: when the test probe card moves from the first plate position to the second plate position and before the probe enters the opening in the plate.
14. The test probe armor of claim 13, wherein the plate is configured to be exerted by the flexible strip. 15. The plate includes an opening for receiving the die when the plate is exerted by the flexible strip and the probe is in electrical contact with the test pad. 14. The test probe protector according to claim 13. 16. The test probe armor according to claim 13, wherein the surface of the plate against which the flexible strip presses is made of a non-conductive material. 17. The test probe protector according to claim 13, further comprising a clamp for fixing said plate substantially at said second plate position.